This research will investigate the factors involved in long-term growth and adaptation of the craniofacial skeletal system following replacement of the mandibular condyle in growing Macaca mulatta. Growth of the maxilla and mandible after bilateral condylar replacement using autogenous 1) mandibular condyles, 2) bone, 3) sternal condyle of the clavicles, and 4) costochondral junction of ribs will be evaluated cephalometrically using 24 juvenile female Macaca mulatta as experimental subjects. Adaptations within the temporomandibular joints will be evaluated histologically two years following transplantation. Based upon previous studies in our laboratory, the following specific hypotheses, or predictions, are put forward: 1) bilateral replacement of the mandibular condyles with autogenous mandibular condyles will result in normal growth of the mandible; 2) bilateral replacement of the mandibular condyle with a bone graft will result in abnormal growth leading to a deficiency of mandibular growth; 3) bilateral replacement of the mandibular condyle with the costochondral junction of a rib will result in uncoordinated growth of the mandible, and; 4) bilateral replacement of the mandibular condyle with the sternal end of the clavicle will result in continued, harmonious growth of the mandible. The results of this study will have a direct and immediate impact on the related clinical problem of growth of the craniofacial complex following lack of growth of the mandibular condyles. The results will assist the surgeon in selecting a transplant which offers the patient a better chance of harmonious facial growth when used clinically to replace a defective mandibular condyle.